Rotary hook for sewing machines



March 31, 1936. cs. SAUER ROTARY HOOK FOR SEWING MACHINES Filed Sept. 7, 1933 Patented Mar. 31, 1936 PATENT OFFICE" 2,035,984 ROTARY.HOOK FOR SEWING MACHINES George Sauer, Berwyn, Ill., assignor to Union Special Machine Company, Chicago, 111., a cor- V 'poration of Illinois Application September 7, 1933, Serial No. 688,512 .13 Claims. (Cl. 112-256) I The invention relates to new and useful improvements in a rotary hook for a lock stitch sewing machine, and more particularly to the means for furnishing'lubrication to the interengaging parts between the rotary'hook and the stationary bobbin casing.

An object of the invention is to provide a means for directing lubricant to the interengaging parts between the rotary hook and the bobbin casing whereby lubrication is furnished said parts while the hook is rotating, and whereby the ports or channels supplying the lubricant to the operating parts may be readily rendered accessible for cleaning. 7 In the drawing, which shows by way of illustration one embodiment of the invention:

Figure l is a Vertical sectional view through a rotary hook, the bobbin casing and the bobbin,

. and a portion of the actuating mechanism for the hook.

Figure 2 is a perspective view of the rotary hook showing the plate covering the channels as separated from the hook in order to make clear the structure of the parts. The parts of the rotary hookwhich cooperate therewith in completing the race for the bobbin case are removed in this view.

Figure 3 is a sectional view at rightangles to one of l the channels in the hook and showing the cover plate therefor.

The invention has to do with a lubricating means for the interengaging parts between the rotary hook and the stationary bobbin casing. The rotary hook is fixed to the end of a rotating shaft and the bobbin casing is mounted within and supported by the rotating hook. Saidbobbin'casing is provided with a circumferential rib which engages a groove or raceway inpthe rotary hook and thus prevents the bobbin'casing from 40 lateral movement in the hook. Extending longitudinally of the shaft and centrally thereof is a port preferably provided with a wicking, and this port is openat the end of the shaft. The shaft extends into the rotary hook and terminates short of the inner face of the hook so as to provide a recess on the inner face of the hook at its axis of rotation. The lubricating oil isfed into this recess from the port in the shaft. The sleeve in which the shaft rotates, as well as the shaft,

has an openingleading to said central port, and means is provided whereby a lubricant may be supplied through these'openings to the central port in the shaft and thus to the recess. On the inner face of the rotating hook are a series of radial channels which extend all the way to the recess in the hook which receives the rib on the bobbin casing. that is, the interengaging parts between the hook and bobbin casing. These channels are opeii on their inner face and are covered'and closed by a removable plate which is 5 .attachedto the hook by screws. This plate extends throughout the greater portion of the length of the channels and serves as a ready means whereby access may be had to the channels for cleaning the same when the plate is 10 removed.

Referring more in detail to the drawing, the invention is shown as applied to a sewing machine having a work support I provided with av suitablebearing bracket in which is mounted a 5 bushing 2, and 'in this bushing 2 is mounted a shaft 3 which carries the rotating hook 4. The shaft 3 is provided with a gear 5 meshing with a driving gear 6. These gears are enclosed in a chamber 1 which may be supplied with a lubri- 20 cating oil so that the gears will run in oil. The specific form of mounting for the rotary hook forms no part of the present invention per se, but is shown, described and claimed in the application filed by Norman V. Christensen and 25 Charles F. Rubel, May 9, 1933, Serial No. 670,186.

The rotary hook 4 is of the usual construction.

It is cup-shaped with portions cut away forming spaced radial webs 8 which are formed as a part of a hub 9. This hub is-slipped onto the end of 30 the shaft 3 and is secured thereto by set screws l0, l0. One side wall of the cup is cut awayto' provide a hook II which is adapted to enter the needle thread loop and carry the same about the bobbin casing containing the bobbin. On the in- 35 ner face of the cup-shaped hook is a groove or raceway [2. The bottom wall and one side wall of the race only is shown in Fig. 2. The parts of 16 which is adapted to engage a member fixed to the frame of the sewing machine so that the 50 bobbin casing is held stationary and does not rotate. The bobbincasing is provided with a circumferential projecting rib l'l which freely engages the raceway or groove I2 in the rotary hook. This bobbin casing is mounted in the hook 55 These parts are of the usual construction'and' I further description thereof is not thought ne'cner.- The means which prevents the bobbin from rotating is of. such a character as to permit this loop to pass freely about the bobbin casing.

essary.

The present invention has particularly to do h a means for lubricating the interengaging wit parts between the bobbin casing and the rotary hook. Whenthe hub 9 is placed on the shaft 3 and secured thereto, there is preferably left a space between the end of the shaft and the inner face of therotating hook, thus forming a recess I8. This recess is open at the inner face of the rotating hook andis disposed at the axis of the rotating hook. Extending radially of each web 8 and centrally along the'sa'me isfachannel l9. This channel I 9 also extends along the inner face of the hook as indicated at ill so that the channel leads all the way from the recess l8 to the raceway I2 in the rotating hook. There are three of these channels as illustrated in the present embodiment of the invention. This number, however, may be varied as desired, and in fact only one channel may v of channels. The channels are open at ,the'inner face of the hook and are covered throughout a greater portion thereof by a plate 2|. Said plate bears against the inner face of the hook and is located between the ho'ok'and the bobbin casing. The plate is secured to the hook by suitable screws v22 passing through openings 23in the plate and threaded into the'hook. This plate extendsout "along the channels, coveringthe same, and thus forming substantially closed ports'leading from I the recess l8 to the channels at the periphery of the hook. This plate covers thereoess J8 andthe channels 19, and when theplate is removed, the recess, and channels are exposed and rendered accessible for cleaning. U

The shaft 3 is provided with a central bore 24 which-extends all the. way to the end of the shaft and thus connects with the recess I 8. Thereis a radial port 25 extendingthrough the shaft to-the'port 24 therein. The'bushing 2 is provided with an opening 26 which, may be brought into register with the opening 25, The work plate. is

provided with an opening 21 which is in register with the opening placed in the bore 24 of the shaft. Lubricating oil fed through the opening?! to the bore 24 in,

the shaft will be fed into the recess l8. Said recess becomes a distributing chamberfor supplying oil to the channels IS; The oil'is caused by centrifugal forc'e,to pass outalong the channels 7 I 9 tojthe race, thus furnishinglubrication for the intere'ngaging parts between the bobbin casing andthe" rotary hook. By removing'th'e bobbin casing from the hook, thisplate 2| may be very easily removed-and thus the channels uncovered,

' as well as the recess "I 8, for the pu 'i oseof freeing the same from any accumulating obstruction therein.

Itis obvious that minor changesjin the details jof constructioncan be made without depafrting I from the spirit of the invention asset forth in "-the appended claims. "Moreover, the reference "herein tothe' means employed for covering the lubricant channel in the rotary hook as a plate" I is to be construed broadly and is intended to combe used instead of a plurality said raceway, ing oil to said 26. A wicking 28 is preferably point adjacent said racewa ing a channel and a removable cover plate there outwardly to the rim hook and plate having; therebetween a series of ports for directing oil out- I prehend any equivalent device affording a wall' for closing the side of the lubricant channel.

Having thus described the invention,. what I claim as new and desire to secure by Letters Patent, is:

1. In a sewing machine, the'c'ombination of a rotary hook, a stationary bobbin casing supported therein, said hook and casing having interengaging parts preventing lateral movement of the casing in said hook, said hook having on its inner face a radial channel extending substantially from the axis thereof to said interengaging parts for directing-lubricating oil to said parts, a plate removably secured to the inner face of said rotating hook and covering said channel through- .out the greater portionof its length, and means whereby lubricating oil may be supplied to said channelat the axis of the hook.

'2. In a sewing-machine, the combination of a rotary hook, a stationary bobbin casing supported therein, said ,hook and easing having, interengaging parts. preventing lateral movement of the casing in said hook, said hook having a recess .on. its inner face at theaxisof rotation thereof and a radial channel extending from-said recess to said interengaging parts fordirecting-lu- ,bricating oil to said parts, a plate removably'secured tothe inner face of said rotating hook and covering said recess and said channel throughout the greater portion of the length of the channel, and means whereby lubricating oil may be supplied to said recess.

3. In a sewin'g'machine, the combination of a rotary hook, a stationary bobbin casing supported therein, said hook and'casing having interengaging parts preventing lateral movement of the casing in said hook, a shaft on which said hook is mounted,.said shaft having a port centrally therej of, a recess insaid hook at the end of the shaft with which said port connects, radial channels extending from said recess to saidinterengaging a plate removably secured to the inner face of said hook and covering said recess and said chanf nelsthroughout the greater portion of thelength of the channels, oil may be supplied to said and means whereby lubricating port in saidshaft.

4 In a sewing machine, thecombination of a rotary hook having a raceway formed therein, a stationary bobbin holding means iournaled in and means for supplying lubricatcentrifugal force, said last-named means includingat least one radially disposed duct leading from anoint, near the axis of said hook to a said-duct comprisfor which renders said channel'readily accessible for cleaning. a I 1 1 5. In a. sewing machine, the combination of a rotary hook, ast'ationary bobbin casing supported portion {of the hook, said radially extending 'wardly to said intereng s'lng Darts,

6 ;'In' asewingmachine, the combination of a portedtherein, said hook and casing rim portion, a hub and spaced radial webs exhaving interengaging parts preventing lateral movement of the. casing in said hook, said hookjhaving a parts. for directing lubricatingoil to said parts,

raceway at a: plurality of points by therein, said hook and casing havlng,inte en8agrotary hook, ,a stationary bobbin casing suptending from the hub portion to the rim portion, means removabiy secured to the inner face of said radial web portions and forming therewith a radial channel extending from the hub portion of the hook to the rim portion for directing oil from a source of supply at the hub to the interengaging parts.

'7. In a sewing machine, the combination of a rotary hook, a stationary bobbin casing supported therein, said hook and casing having interengaging parts preventing lateral movement of the casing in said hook, said hook having a rim portion, a hub and spmed radial webs extending from the hub portion to the rim portion, means removably secured to the inner face of said radial web portions and forming with at least one of said webs a radial channel extending from the hub portion of the hook to the rim portion for directing oil from a source of supply at the hub to the interengaging parts, said rim portion having a channel in alinement with the channel in a web portion and leading to the interengaging parts.

8. I a sewing machine,,the combination of a rotary hook, a stationary bobbin casing supported in a raceway formed in said hook and restrained against lateral movement relative to said hook by the sides of said raceway, said rotary hook comprising a hub and a rim portion connected by a plurality of spaced radial webs, an oil channel formed in the inner face of one of said webs and extending from the hub to the rim portion and-a plate secured to said hook and covering said channel in the web thereof.

9. In a sewing machine, the combination of a rotary hook, a stationary bobbin casing supported in a raceway formed in said hook and restrained against lateral movement relative to said hook by the sides of said raceway, said rotary hook comprising a hub and a rim portion connected by a plurality of spaced radial webs, an oil channel having communicating portions formed on the inner face of one of said webs and on the inner face of said rim portion and extending from said hub to said raceway, and a plate secured to said hook and covering said channel in the web thereof.

10. In a sewing machine, the combination of a rotary hook, a stationary bobbin casing supported in a raceway formed in said hook and restrained against lateral movement relative to said hook by the sides of said raceway, said rotary hook comprising a hub and a rim portion connected by a plurality of spaced radial webs, an oil channel formed in the inner face of each radial web and extending from the hub to the inside of said rim portion, and a. removable plate secured to said hub portion and covering said channels.

11. In a sewing machine, the combination of a rotary hook, a stationary bobbin casing supported therein, said hook and casing having interengaging parts preventing lateral movement of the casing in said book, a shaft on which said hook is mounted, said shaft having an oil conveying port centrally thereof, and said hook having an axially bored hub portion engaging the shaft and forming a recess at the end of the shaft connected with said port, said hook having on the inner face thereof radial channels extending from the recess to said interengaging parts for directing lubricating oil to said parts, means removably secured to the inner face of said hook for covering the recess at the hub of the hook and the channels leading therefrom throughout a greater portion thereof, and means whereby lubricating oil may be supplied to said port in said shaft.

12. In a sewing machine, the combination of a rotary hook, a stationary bobbin casing supported therein, said hook and easing having interengaging parts preventing lateral movement of the easing in said hook, a member rigidly secured to said hook and forming therebetween at a face of the hook a series of radially extending channels for directing oil outwardly from the hub of the hook to the interengaging. parts.

13. In a sewing, machine, the combination of a rotary hook, a stationary bobbin casing supported therein, said hook and casing having interengaging parts preventing lateral movement of the easing in said hook, and means removably attached to the inner face of the hook and forming therewith a series of radially extending channels for directing oil outwardly from the hub of the hook to the interengaging parts.

GEORGE SAUER. 

